Updated to Big Sur 11.2.3 and now can't see flagged emails in mac mail client

My mac updated to Big Sur 11.2.3, now I can't see my flagged emails. I have tried restarting my mac, restarting mail, rebuilding the mail box, and also updating the filter, and nothing works. I have tried setting up a new mailbox with a 'flagged email' filter and that doesn't work either. Can someone please help, as I use flagged emails a lot as part of my to do list!